Device for opening the flaps of envelopes

ABSTRACT

A stripper device for lifting and opening the flaps of envelopes transported by a conveyor to a work station prior to transport of the envelopes to a filling station of an envelope stuffing machine includes a pair of conveyor rollers for advancing an envelope in a transport plane to the work station and a pair of discharge rollers for transporting the envelope from the work station towards the filling station. At a position spaced above the transport plane and extending transversely thereto there is provided a stripper member adapted to be moved between an inoperative position spaced above the envelope and an operative position in which the stripper member is effective to engage and lift up and open the flap of the envelope. The lead edge of the stripper member, intermediate the ends of the stripper member, is provided with a recessed knife edge for entering between the body and the flap of the envelope to provide positive gripping and opening of the flap. A spring element is provided at a position beneath the transport plane and acts to urge the envelope in an upward direction towards the knife edge of the lowered stripper member to further assure that the envelope in the zone of the flap is pressed firmly against the knife edge of the stripper member thereby facilitating the entry of the knife edge between the envelope body and the flap.

United States Patent [191 Dorer [415] Oct. 7, 1975 [75] Inventor:Wilfried Dorer,Donaueschingen,

Germany [73] Assignee: Mathias Bauerle GmbH,

St. Georgen, Germany [22] Filed: Mar. 25, 1974 21 Appl. No.: 454,252

[30] Foreign Application Priority Data Apr. 26, 1973 Germany 2321128[52] US. Cl 53/58; 53/384 [51] Int. Cl. B65B 57/04; B65B 43/26 [58]Field of Search 53/29, 58, 187, 266 A,

[56] References Cited 7 UNITED STATES PATENTS 1,305,390 6/1919 McCarthy53/384 X 1,886,119 11/1932 Price 53/187 2,019,211 10/1935 Clare 53/266 AX 2,839,880 6/1958 Boughton.... 53/266 A X 3,473,288 10/1969 Nakamura53/58 3,550,351 12/1970 Gombault 53/187 3,568,401 3/1971 Bonsch 53/266 XFOREIGN PATENTS OR APPLICATIONS 1,045,672 10/1966 United Kingdom 53/266A Primary Examiner-Travis S. McGehee Assistant Examiner-John SiposAttorney, Agent, or Firm-Sol 1L. Goldstein; Russell L. Root; Ray S. Pyle[5 7] ABSTRACT A stripper device for lifting and opening the flaps ofenvelopes transported by a conveyor to a work station prior to transportof the envelopes to a filling station of an envelope stuffing machineincludes a pair of conveyor rollers for advancing an envelope in atransport plane to the work station and a pair of discharge rollers fortransporting the envelope from the work station towards the fillingstation. At a position spaced above the transport plane and extendingtransversely thereto there is provided a stripper member adapted to bemoved between an inoperative position spaced above the envelope and anoperative position in which the stripper member is effective to engageand lift up and open the flap of the envelope. The lead edge of thestripper member, intermediate the ends of the stripper member, isprovided with a recessed knife edge for entering between the body andthe flap of the envelope to provide positive gripping and opening of theflap. A spring element is provided at a position beneath the transportplane and acts to urge the envelope in an upward direction towards theknife edge of the lowered stripper member to further assure that theenvelope in the zone of the flap is pressed firmly against the knifeedge of the stripper member thereby facilitating the entry of the knifeedge between the envelope body and the flap.

9 Claims, 5 Drawing Figures US. Patent Oct. 7,1975

DEVICE FOR OPENING THE FLAPS OF ENVELOPES BACKGROUND OF THE INVENTION Ina known prior art device of this general kind there is shown anarrangement for transporting an envelope to a position under a strippermember at the work station of the envelope stuffing machine. Thestripper member extends in a direction transverse to the direction ofenvelope feed and extends over the whole width of the transport plane.The lead edge of the stripper member is also provided with a knife edgeand the stripper member is arranged for movement between raised andlowered positions. In operation, as the front edge of the envelopeapproaches the stripper member, the stripper member is lowered to theside and onto the envelope in such a way so as to grip, raise and foldback the flap of the envelope.

However, in order to assure positivve lifting of the flap by thestripper member, this prior art device also requires that a suitableblast of compressed air be directed towards the flap so as to partiallylift the flap to permit positive insertion of the stripper memberthereunder. This partial opening of the flap by the air blast isrequired before engagement of the flap by the knife edge since theweight of the stripper member in its lowered position rests on theentire length of the envelope. Also, if the knife edge of the strippermember were to be an extremely sharp cutting edge to provide for morepositive stripping of the flap without the aid of an air blast therewould be the danger of the sharp edge cutting the flap of the envelopeat its fold.

SUMMARY OF THE INVENTION The present invention provides a device forlifting and opening the flap of an envelope at a work station of anenvelope stuffing machine without the need of a preliminary opening ofthe flap by an air blast as disclosed in the prior art device.

It is an object of the present to provide an envelope flap openingdevice including a stripper member having a knife edge recessed from apair of rounded lead edges of the stripper member. The knife edgeextends laterally over only a central portion intermediate the roundedlead edges of the stripper member. The rounded lead edges prevent theknife edge from coming into contact with the fold and cutting the flapat the fold, and permit the use of a knife edge having an extremelysharp edge which, even when the flap lies flat on the body of theenvelope, can grip and lift the flap in a positive manner without theassist of a preliminary air blast as required in the prior art device.

It is another object of the invention to provide a spring-pressureelement arranged below the knife edge. The spring-pressure element isnarrower than the length of the knife edge such that the pressureelement presses firmly against the underside of the knife edge only inthe zone of the point of the flap to permit positive gripping andlifting of the flap of the envelope by the knife edge.

Other objects, features and advantages will appear hereinafter as thedescription proceeds.

- IN THE DRAWING FIG. 1 is a plan view, partially broken away, showing astripper device for opening the flap of an envelope in accordance withthe present invention;

FIG. 2 is an end elevation, in section, of the stripper device as viewedon the line A.A in FIG. 1 and showing the stripper device in a loweredposition for lifting the envelope flap;

FIG. 3 is an enlarged sectional end view, partially broken away, showingthe stripper device inserted between the flap and the body of theenvelope;

FIG. 4 is a partial section of the stripper device showing the knifeedge of the stripper in detail; and

FIG. 5 is a sectional end view of the stripper device as viewed on theline B-B in FIG. 1, partially broken away, similar to FIG. 2 but showingthe stripper in a raised position.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIGS. 2 and 5there is shown a pair of conveyor rollers 3 and 4 for transporting anenvelope 1 (shown in phantom in FIG. 1) along a path to a work station,and a pair of discharge rollers 5 and 6 for transporting the envelopefrom the work station to a filling station of an envelope stuffingmachine. The conveyor rollers 3 and 4 are driven at the same peripheralspeed as the discharge rollers 5 and 6 and transport the envelope 1 inthe direction of arrow 2 shown in FIG. 2.

A guide plate 7 is provided for supporting the envelope 1 at the workstation and the upper surface of the guide plate defines a transportplane in alignment with the nip of the conveyor rollers 3 and 4 and thenip of the discharge rollers 5 and 6. A separator or stripper member 10is pivotally supported in a pair of side plates 8 and 9 and extendstransverse to the transport plane and the direction of envelope feedsubstantially the whole width of the guide plate 7. The separator member10 is positioned above the guide plate 7 immediately' ahead of thedischarge roller 5, and is arranged for swinging movement between aninoperative raised position shown in FIG. 5 and an operative loweredposition as shown in FIGS. 2 and 3 wherein the foot mem ber of thestripper 10 is in engagement with the envelope to separatingly engageand lift a closed flap 21 of the envelope 1.

The separator member 10 is moved between its raised and loweredpositions in response to energization of a solenoid 11 activated by amicroswitch 12. The microswitch 12 is provided with a feeler arm 13projecting through an opening 14 in the guide plate 7 and extends frombelow the guide plate into the path of movement of the envelope 1 beingtransported to the work station. The envelope 1 is transported to thework station with the flap 21 thereof facing upwardly and with the flaptrailing a lead edge 15 of the envelope in the direction of envelopetransport. Thus, as the lead transverse edge 15 (FIG. 5) of the envelope1 is transported beyond a pair of rounded lead edges 16 of the raisedstripper member 10, the edge 15 of the envelope strikes the feeler arm13 thereby actuating the microswitch 12 and energizing the solenoid 11to effect swinging movement of the stripper member 10 from the raised tothe lowered position.

As best shown in FIGS. 1 and 4, extending laterally between and parallelwith the pair of rounded lead edges 16 of the stripper member 10, therounded lead edges 16 being in aligned and spaced apart relationshipwith each other, there is provided a sharp knife edge 17 recessed fromthe rounded lead edges 16 by a distance a. The length of the knife edge17, indicated by the reference character. 1 is about 20% 25% of thetotal length of the stripper member 10.

A spring-pressure element in the form of a leaf spring 18 is mounted onthe underside of the guide plate 7 and projects upwardly through anopening 19 in the guide plate 7 and extends into the transport plane ofthe envelope path. The leaf spring 18 is biased in an upward directionso as to press against the underside of the stripper member 10 in thearea of the knife edge 17 when the stripper member 10 is in the loweredposition as shown in FIG. 2. The width or surface of the leaf spring 18,represented by the reference character 1 in FIG. 4, is preferable aboutone-half the length 1 of the knife edge 17 to assure that the envelopeis pressed in the zone of the flap firmly against the underside of theknife edge 17 of the stripper member 10 for positive gripping andlifting of the envelope flap 21 by the knife edge 17.-

Subsequent to the initial opening of the flap 21 by the knife edge 17 asshown in FIG. 2, as the envelope 1 is further transported toward thedischarge rollers 5 and 6 theflap 21 continues to be raised by thestripper member 10 until such time as the rounded lead edges 16 of thestripper member 10 arrive at a fold 22 of the flap 21 as shown in FIG.3. In this position the flap 21 ,is in its extreme open position and theenvelope is in readiness for further transport from the work station tothe filling station of the envelope stuffing machine.

After the flap of the envelope 1 is opened, further transport of theenvelope by the discharge rollers 5 and 6 moves the envelope from thework station towards the filling station. As the envelope is moved outof the work station and the trailing edge of the envelope travels beyondand releases the feeler arm 13, the microswitch 12 activates thesolenoid 11 which restores the stripper member 10 to the inoperativeraised position.

Because the knife edge 17 is recessed from the rounded lead edges 16 ofthe stripper member 10 by an amount indicated by the reference charactera, the knife edge 17 does not come into contact with the fold 22 of theflap 21 thereby eliminating the possibility of the knife edgel7..cutting the fold 22 of the flap 21. Also, as a result of the leafspring 18 urging the envelope firmly against the underside of the knifeedge 17 to assure positive gripping, lifting and opening of the flap 21,the possibility of a tip 20 of the flap 21 sliding under the strippermember 10, such that the knife edge 17 would fail to engage and lift theflap 21, is virtually eliminated. l

From the foregoing it will be seen that the present invention provides anovel arrangement of a stripper member for lifting and opening the flapsof envelopes at the work station for further transport to the fillingstation of an envelope stuffing machine. The recessed knife edge of thestripper member together with the pressure spring element acting againstthe envelope in the zone of the flap to urge it into firm engagementwith the knife edge provide an extremely reliable means for insuringthat the knife edge will enter between the body and the flap of theenvelope to thereby raise the flap to the open position. Additionally,the rounded lead edges of the stripper member are effective toprogressively raise the flap to the open position without danger of theknife edge cutting the fold of the flap of the envelope.

I claim:

1. A stripper device for lifting and opening a flap of an envelope at awork station prior to transporting the envelope to a filling station ofan envelope stuffing machine, comprising:

means for transporting an envelope having a folded flap closure to thework station with the flap facing upwardly and trailing a lead edge ofthe envelope in the direction of envelope transport;

a guide plate defining a transport plane for supporting an envelope atthe work station;

a stripper member pivotally mounted above and transverse to thetransport plane for movement between an inoperative position spaced fromthe envelope at the work station and an operative position in engagementwith the envelope, said stripper member comprising a continuous singularmember having a lead edge comprising rounded segments at its lateralends and a knife blade section intermediate said ends and recessed fromthe rounded lead edges;

biasing means for urging the envelope against said stripper member; and

means actuable by the lead edge of the envelope transported to the workstation for moving the stripper member from the inoperative position tothe operative position whereby the knife blade engages and lifts theflap of the envelope and the rounded lead edges open and fold back theflap of said envelope and prevent the knife blade from coming intocutting engagement with the fold of the flap.

2. A stripper device as set forth in claim 1 in which the biasing meansincludes a spring pressure element positioned beneath the transportplane and having a surface thereof acting against the envelope at thework station for pressing the envelope firmly against the knife bladewhen the stripper member is in the operative position.

3. A stripper device as set forth in claim 2 in which the surface of thespring pressure element extends laterally a distance less than thelength of the knife blade so as to act against the envelope in a zone ofthe envelope flap.

4. A stripper device as set forth in claim 1 in which the strippermember is moved from the operative position to the inoperative positionin response to actuation of the last-named means which is actuated inresponse to movement of the envelope out of the work station and towardsthe filling station by the transport means.

5. A stripper device for lifting and opening a flap of an envelope at awork station prior to transport of the envelope to a filling station ofan envelope stuffing machine, comprising:

means for delivering an envelope having a folded flap closure to thework station;

a transport plane for supporting an envelope at the work station;

a stripper member pivotally mounted above the transport plane formovement between an inoperative position and an operative position inengagement with the envelope at the work station, said stripper membercomprising a continuous singular member having a lead edge comprisingrounded segments at its lateral ends and a knife blade sectionintermediate said ends and recessed from the rounded lead edges;

biasing means for urging the envelope against said stripper member; and

means responsive to the presence of an envelope at the work station formoving the stripper member from the inoperative position to theoperative position whereby the knife blade engages and lifts the flap ofthe envelope and the rounded lead edges open and fold back the flap ofsaid envelope and prevent the knife blade from coming into cuttingengagement with the fold of the flap.

6. A stripper device as set forth in claim 5 in which the biasing meansincludes a spring pressure element positioned beneath the transportplane and having a surface thereof acting against the envelope at thework station for pressing the envelope firmly against the knife bladewhen the stripper member is in the operative position.

7. A stripper device as set forth in claim 6 in which the surface of thespring pressure element extends laterally a distance less than thelength of the knife blade so as to act against the envelope in a Zone ofthe envelope flap.

8. A stripper device as set forth in claim 5 in which the strippermember is moved from the operative position to the inoperative positionin response to actuation of the last-named means which is actuated inresponse to movement of the envelope out of the work station and towardsthe filling station by the transport means.

9. A device for lifting and Opening a flap of an envelope at a workstation prior to transporting the envelope to a filling station of anenvelope stuffing machine, comprising:

means for transporting the envelope having a folded flap closure along apath to a work station in a position that exposes the flap containingside of the en velope so that the flap is transverse to the path ofmovement and opens in a direction countercurrent the envelope transportdirection;

a separator member pivotally mounted above and transverse to the path ofthe envelope, said separator member comprising a continuous singularmember having a lead edge comprising rounded segments at its lateralends and a knife blade section intermediate said ends and recessed fromthe rounded lead edges; and

biasing means for urging the envelope against said separator member.

1. A stripper device for lifting and opening a flap of an envelope at awork station prior to transporting the envelope to a filling station ofan envelope stuffing machine, comprising: means for transporting anenvelope having a folded flap closure to the work station with the flapfacing upwardly and trailing a lead edge of the envelope in thedirection of envelope transport; a guide plate defining a transportplane for supporting an envelope at the work station; a stripper memberpivotally mounted above and transverse to the transport plane formovement between an inoperative position spaced from the envelope at thework station and an operative position in engagement with the envelope,said stripper member comprising a continuous singular member having alead edge comprising rounded segments at its lateral ends and a knifeblade section intermediate said ends and recessed from the rounded leadedges; biasing means for urging the envelope against said strippermember; and means actuable by the lead edge of the envelope transportedto the work station for moving the stripper member from the inoperativeposition to the operative position whereby the knife blade engages andlifts the flap of the envelope and the rounded lead edges open and foldback the flap of said envelope and prevent the knife blade from cominginto cutting engagement with the fold of the flap.
 2. A stripper deviceas set forth in claim 1 in which the biasing means includes a springpressure element positioned beneath the transport plane and having asurface thereof acting against the envelope at the work station forpressing the envelope firmly against the knife blade when the strippermember is in the operative position.
 3. A stripper device as set forthin claim 2 in which the surface of the spring pressure element extendslaterally a distance less than the length of the knife blade so as toact against the envelope in a zone of the envelope flap.
 4. A stripperdevice as set forth in claim 1 in which the stripper member is movedfrom the operative position to the inoperative position in response toactuation of the last-named means which is actuated in response tomovement of the envelope out of the work station and towards the fillingstation by the transport means.
 5. A stripper device for lifting andopening a flap of an envelope at a work station prior to transport ofthe envelope to a filling station of an envelope stuffing machine,comprising: means for delivering an envelope having a folded flapclosure to the work station; a transport plane for supporting anenvelope at the work station; a stripper member pivotally mounted abovethe transport plane for movement between an inoperative position and anoperative position in engagement with the envelope at the work station,said stripper member comprising a continuous singular member having alead edge comprising rounded segments at its lateral ends and a knifeblade section intermediate said ends and recessed from the rounded leadedges; biasing means for urging the envelope against said strippermember; and means responsive to the presence of an envelope at the workstation for moving the stripper member from the inoperative position tothe operative position whereby the knife blade engages and lifts theflap of the envelope and the rounded lead edges open and fold back theflap of said envelope and prevent the knife blade from coming intocutting engagement with the fold of the flap.
 6. A stripper device asset forth in claim 5 in which the biasing means includes a springpressure element positioned beneath the transport plane and having asurface thereof acting against the envelope at the work station forpressing the envelope firmly against the knife blade when the strippermember is in the operative position.
 7. A stripper device as set forthin claim 6 in which the surface of the spring pressure element extendslaterally a distance less than the length of the knife blade so as toact against the envelope in a zone of the envelope flap.
 8. A stripperdevice as set forth in claim 5 in which the stripper member is movedfrom the operative position to the inoperative position in response toactuation of the last-named means which is actuated in response tomovement of the envelope out of the work station and towards the fillingstation by the transport means.
 9. A device for lifting and opening aflap of an envelope at a work station prior to transporting the envelopeto a filling station of an envelope stuffing machine, comprising: meansfor transporting the envelope having a folded flap closure along a pathto a work station in a position that exposes the flap containing side ofthe envelope so that the flap is transverse to the path of movement andopens in a direction counter-current the envelope transport direction; aseparator member pivotally mounted above and transverse to the path ofthe envelope, said separator member comprising a continuous singularmember having a lead edge comprising rounded segments at its lateralends and a knife blade section intermediate said ends and recessed fromthe rounded lead edges; and biasing means for urging the envelopeagainst said separator member.